#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <getopt.h>
#include <pthread.h>
#include <ctype.h>

#define BACKLOG                   13
#define MSG_STR                  "OK-OK-OK-OK_1028!"

typedef void *(THREAD_BODY) (void *thread_arg);

void *thread_worker(void *ctx);
int thread_start(pthread_t * thread_id, THREAD_BODY * thread_workbody, void *thread_arg);
void print_usage(char *progname)
{
	printf("%s usage: \n", progname);
       	printf("-p(--port): sepcify server listen port.\n");
	printf("-h(--Help): print this help information.\n");
	return ;
}
int main(int argc, char **argv)
{
	int                      sockfd = -1;
	int                      rv = -1;
	struct sockaddr_in       servaddr;
	struct sockaddr_in       cliaddr;
	socklen_t                len;
	int                      port = 0;
	int                      clifd=-1;
	int                      ch;
	int                      on = 1;
	pthread_t                tid;
	struct option            opts[] = {
		{"port", required_argument, NULL, 'p'},
		{"help", no_argument, NULL, 'h'},
		{NULL, 0, NULL, 0}
	};
	while( (ch=getopt_long(argc, argv, "p:h", opts, NULL)) != -1 )
	{
		switch(ch)
		{
			case 'p':
				port=atoi(optarg);
				break;
			case 'h':
				print_usage(argv[0]);
				return 0;
		}
	}
	if( !port )
	{
		print_usage(argv[0]);
		return 0;
	}
	sockfd=socket(AF_INET, SOCK_STREAM, 0);
	if(sockfd < 0)
	{
		printf("Create socket failure: %s\n", strerror(errno));
		return -1;
	}
	printf("Create socket[%d] successfully!\n", sockfd);

	setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
	
	memset(&servaddr, 0, sizeof(servaddr));
	servaddr.sin_family=AF_INET;
	servaddr.sin_port = htons(port);
	servaddr.sin_addr.s_addr = htonl(INADDR_ANY); /* listen all the IP address on this host */
		
	rv=bind(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr));
	if(rv < 0)
	{
	      	printf("Socket[%d] bind on port[%d] failure: %s\n", sockfd, port, strerror(errno));
	   	return -2;
    	} 
	listen(sockfd, BACKLOG);    
       	printf("Start to listen on port [%d]\n", port);
  	while(1)
	{
      		len=sizeof(cliaddr);
		printf("Start accept new client incoming...\n");
      		clifd=accept(sockfd, (struct sockaddr *)&cliaddr, &len);
    		if(clifd < 0)
   		{
	   		printf("Accept new client failure: %s\n", strerror(errno));
	 		continue;
		}
		printf("Accept new client[%s:%d] successfully\n", inet_ntoa(cliaddr.sin_addr), ntohs(cliaddr.sin_port));
		/* !!!! Think about here: why pass clifd but not &clifd ? !!! */
		thread_start(&tid, thread_worker, (void *)clifd);
	}
	close(sockfd);
	return 0;
}
int thread_start(pthread_t * thread_id, THREAD_BODY * thread_workbody, void *thread_arg)
{
	int              rv=-1;
	pthread_attr_t   thread_attr;
	if( pthread_attr_init(&thread_attr) )
	{
		printf("pthread_attr_init() failure: %s\n", strerror(errno));
		goto CleanUp;
	}
	if( pthread_attr_setstacksize(&thread_attr, 120*1024) )
	{
		printf("pthread_attr_setstacksize() failure: %s\n", strerror(errno));
		goto CleanUp;
	}
	if( pthread_attr_setdetachstate(&thread_attr, PTHREAD_CREATE_DETACHED) )
	{
		printf("pthread_attr_setdetachstate() failure: %s\n", strerror(errno));
		goto CleanUp;
	}
	/* Create the thread */
	if( pthread_create(thread_id, &thread_attr, thread_workbody, thread_arg) )
	{
		printf("Create thread failure: %s\n", strerror(errno));
		goto CleanUp;
	}
	rv = 0;
                                               
CleanUp:
	/* Destroy the attributes of thread */
	pthread_attr_destroy(&thread_attr);
	return rv;
}
void *thread_worker(void *ctx)
{
	int      clifd; 
	int      rv;
	char     buf[1024];
	int      i;
	if( !ctx )
	{
		printf("Invalid input arguments in %s()\n", __FUNCTION__);
		pthread_exit(NULL);
	}
	clifd = (int)ctx;
	printf("Child thread start to commuicate with socket client...\n");
	while(1)
	{
		memset(buf, 0, sizeof(buf));
		rv=read(clifd, buf, sizeof(buf));
		if( rv < 0)
		{
			printf("Read data from client sockfd[%d] failure: %s and thread will exit\n", clifd, strerror(errno));
			close(clifd);
			pthread_exit(NULL);
		}
		else if( rv == 0)
		{
			printf("Socket[%d] get disconnected and thread will exit.\n", clifd);
			close(clifd);
			pthread_exit(NULL);
		}
		else if( rv > 0 )
		{
			printf("Read %d bytes data from Server: %s\n", rv, buf);
		}

		/* convert letter from lowercase to uppercase */
		for(i=0; i<rv; i++)
		{
			buf[i]=toupper(buf[i]);
		}
		
		rv=write(clifd, MSG_STR, strlen(MSG_STR));
		if(rv < 0)
		{
			printf("Write to client by sockfd[%d] failure: %s and thread will exit\n", clifd, strerror(errno));
			close(clifd);
			pthread_exit(NULL);
		}
	}
}
